This application relates generally to helmets, and more particularly to helmet structures worn by cyclists and having retention straps for retaining the helmets to the heads of cyclists.
Safety helmets, as worn by bicyclists, motorcyclists, skaters, and others, typically employ a thick (20 to 50 mm) layer of crushable, synthetic resin foam, extending over and about the wearer's head to mitigate impact. In many designs, ventilation openings or holes are formed to extend in or through the helmet body. It was found that such holes reduced the impact strength of the helmet body, and particularly proximate the holes. In order to prevent reduction in impact strength, a stiff, outer shell was employed, the helmet body itself would be made thicker, or the entirety of the crushable foam would be made of higher density material. However, all of these approaches increase substantially the overall weight of the helmet. No way was known to achieve increased strength, without increasing helmet body thickness or weight.
Further, when safety straps are to be anchored to the helmet body, it was necessary to thread the straps through holes in the main body of the helmet after it was molded, which was time consuming. There was no way to mold the main body with the straps already installed in position in the main body.